The present invention provides a method for treating neuropathic pain.
For clinical purposes, pain can be categorized into three groups: (1) acute pain; (2) continuous pain in terminally ill patients; and(3) other forms of chronic pain. In acute pain, a specific noxious stimulant of limited duration can be identified. An additional distinction that is relevant to chronic pain is the difference between pain caused by a tissue-damaging process that excites nociceptive afferents and pain caused by pathologic changes in nociceptive neurons (neuropathic pain). Neuropathic pain typically persists and may even have its onset long after the original causative stimulus has been removed.
There are drugs used in the treatment of pain which are known in the literature and to the skilled artisan. See, for example, Merck Manual, 16th Ed. (1992), p. 1409. However, there is a demand for more active analgesic agents with diminished side effects and toxicity and which are non-addictive. The ideal analgesic would reduce the awareness of pain, produce analgesia over a wide range of pain types, act satisfactorily whether given orally or parenterally, produce minimal or no side effects, be free from tendency to produce tolerance and drug dependence.
Applicants have discovered that certain phenyl oxazoles and phenyl thiazoles can provide many of the characteristics of an ideal analgesic for the treatment of neuropathic pain. It is known that these phenyl oxazoles and phenyl thiazoles are useful for treating neurodegeneration. Surprisingly, and in accordance with this invention, Applicants have discovered that these compounds can be useful for the treatment of neuropathic pain and could address a long felt need for a safe and effective treatment.